So Ando turns evil then somewhere along the line, guessing the red lightning he can shoot out of his hands now is similar to star wars red = bad, blue = good (thinking of the light sabres)

That would be too predictable. And you saw how hiro was acting without a quest of some sort. I expect Hiro will be the one that turns bad. I doubt he'll do anything really evil, just in other peoples eyes it'll seem evil while to him it would seem right. Just like the end of season 2 with peter helping adam. On the lightsaber note don't forget green is good too. lol. And purple means u just a bad motherf*****. My boy Sam the black jedi.

that seems far too obvious for me, by revealing it at the beginning of the season, it makes it seem like thats what the writers want you to think, then will reveal later on that all is not what it seems, and that hiro is the evil one, or that its gabriel or peter doing their illusion thing.
having said that, mohinder appeared to change slightly after taking the serum (personality wise i mean) so if ando does take the serum it has an adverse affect on his friendship with hiro?

Perhaps blue lightning is set to kill, and red is set to stun. You never know what'll happen with this show.

I've seen some other threads suggesting perhaps that Ando we see in the future isn't Ando at all.

Also seemed strange that they'd be fighting over the formula half as som kind of massive devastation is seconds away. Seems like the time for formula's had passed.

For that matter, Hiro should have just leaped back 5 minutes in time after the formula was stolen, and kept himself from opening the safe -- but where's the fun in that.